The present invention relates to a high purity hafnium material with a reduced zirconium content contained in the hafnium, a target and thin film formed from this material, and a manufacturing method of high purity hafnium.
Conventionally, there are numerous documents relating to the manufacture of hafnium, and, since hafnium and zirconium are very similar in terms of atomic structure and chemical property, the inclusion of zirconium or the inclusion of zirconium in hafnium was never really acknowledged as a problem as exemplified below.
Hafnium and zirconium are superior in heat resistance and corrosion resistance, and are characterized in that they have a strong affinity with oxygen and nitrogen. And, since the oxides or nitrides thereof have superior stability in high temperatures, they are utilized as ceramics in the atomic power generation or as fire-resistant materials in the manufacture of steel or castings. Further, recently, these are also being used as electronic materials or optical materials.
The manufacturing method of metal hafnium or metal zirconium is proposed as the same manufacturing method. As such example, there is a method of reacting a fluorine-containing zirconium or hafnium compound with metal aluminum or magnesium in inert gas, reducing gas or vacuum at a temperature of 400° C. or higher (e.g., refer to Japanese Patent Laid-Open Publication No. S60-17027); a manufacturing method of reducing zirconium chloride, hafnium chloride or titanium chloride to obtain the respective metals thereof characterized in the sealing metal (e.g., refer to Japanese Patent Laid-Open Publication No. S61-279641); a manufacturing method of hafnium or zirconium characterized in the reaction container structure upon reducing zirconium tetrachloride or hafnium tetrachloride with magnesium and the manufacturing technique thereof (e.g., refer to Japanese Patent Laid-Open Publication No. S62-103328); a method of manufacturing chloric-, bromic- or iodic-zirconium, hafnium, tantalum, vanadium or niobium compound vapor by introducing these into a crucible (e.g., refer to PC(WO)1991-501630); a method of refining zirconium or hafnium chloride or an acid chloride aqueous solution with strongly basic anion exchange resin (e.g., refer to Japanese Patent Laid-Open Publication No. H10-204554); and a method of collecting zirconium via solvent extraction (e.g., refer to Japanese Patent Laid-Open Publication No. S60-255621).
As described in the foregoing documents, although there are numerous refining methods and extraction methods of zirconium and hafnium, the inclusion of zirconium or the inclusion of zirconium in hafnium was never really acknowledged as a problem.
Nevertheless, in recent years, deposition on electronic components using hafnium silicide is being demanded. In such a case, even zirconium is an impurity, and there is a possibility that the required characteristics of the hafnium raw material may become unstable. Therefore, there is demand for a high purity hafnium material with reduced zirconium, and a target and thin film formed from such a material.
However, since there was no notion of separating hafnium from zirconium as described above, the actual condition is that there is no efficient and stable manufacturing technology for obtaining the foregoing high purity hafnium material with reduced zirconium, and a target and thin film formed from such a material.